I practice everyday, from half hour to an hour, and on mondays and thursday I have a three hour jazz band practice wich I play through a good long portion of. I'm a freshman and I started in 4th grade. It never hurt until about the end of 8th grade. Last night I looked at my lower teeth and they're really uneven. Could that be a problem??

If your embouchure is correct (and not under developed) there will never be any cut or mark on your lower lip. I am a profesional saxophonist and saxophone teacher. I play for hours and hours every day and never have a single cell missing from my lower lip. A proper saxophone embouchure has NO pressure from your lower teeth against the reed. The right places to get "sore" when you become fatigued is at the corners of the mouth. You should feel like your mouth is more open than what you feel now. And about the pitch going flat -- this will cause the pitch to go down and you will have to re-adjust your mouthpiece a bit. If it is going TOO flat (meaning mpc compensation won't correct it), you need to firm up those corners a little bit. For more info on the embouchure, check out Larry Teal's "The Art of Saxophone Playing." It's a great reference to have with an excellent chapter on the embouchure. good luck.